If i'm 3-4 weeks pregnant verified via blood when was conception? last menstural may, dont remember the specific date nor do i have a due date yet.

Not enough info: If you do not know the date of your last period or your due date then there is no way that anyone can tell you what day you conceived. That information is needed to calculate conception. Alternatively, If you are only 3-4 weeks pregnant you could think back to when you had sex 1-2 weeks ago and that gives you an estimated time range.

Can't say: Without knowing your LMP or your due date, it's hard to say. When we talk about number of weeks gestation, we count from the first day of your LMP. Conception actually occurs two weeks later. So, if you say you are only 3-4 weeks pregnant, to me that means conception occurred only 1-2 weeks ago.